Destructible hollow form



Feb. 20, 1 945. RE ER 2,369,892

DESTRUCTIBLE HoLLdw FORM Filed 001:. 28, 1943 2 Sheets-Sheet 1 NNNNNN OR I L/LL/A/v L. G/PL'NEKE/P aavz Pa ATTORNEYS Patented Feb. 20, 1945 s PATEN r OFFICE niasrauc rmm HOLLOW FORM Lillian L. Greneker, New Yorlr, N.-Y. Application October zs, 1943," Serial-; No. 507,989

(c1.1s+45) I I that way 'of applying the paper facilitates appli- 12 Claims.

.This invention relates to destructible forms such as those used in the manufacture of fuel tanks and cells or other'articles made of rubber or other material. The fuel tank or cell or'other article." is made. on the form, after which the form isv destroyed and removed. Such forms.

must be cheap to manufacture, light, strong and rigid, accurate as to shape and dimensions, and not subject to change of shape or dimensions under' conditions such as heat and moisture to which they may be subjected in use. Such forms also must be capable of being readily destroyed and removed from the fuel tank or cell'or article which may be made on them, even though the opening in the article through which the pieces of the form must be removed is comparatively small. The present invention is not concerned with the particular shape of the form, but merely with its construction, since of ,course the constructions hereinafter described may be used in forms having an infinite variety of shapes and sizes.

The general object oftthe present invention is to provide improved form constructions which satisfy particularly well the above mentioned requirements'. To these ends, the invention is characterized by the use of flexible sheet material, suchas' heavy paper made of wood-pulp, which is bond ed tothe inner sides of the molded frangible material, such as plaster of Paris, of which the forms are made in a mold to the exact shape and size desired. Wherever the term paper is hereinafter used it is intended to include all equivacation of the paper to rounded or curved surfaces,

and also-because it permits the escape of air from beneath the paper and'substantially eliminates air pockets between the paper, and the plaster in the wall of theform. In some cases, it may be desirable to increase'the reinforcing effect by applying two or more layers of pieces of paper,

bonded together and to the inside of the plaster in the wall of the form..

Where it is desirable to reinforce wall areas of considerable size, the paper may be folded or otherwise arranged before or at the time of applying-it to the inside of the wall of the form, sothat a reinforcing effect isobtained by fins composed of paper and plaster bonded together and bonded to the inside of the wall of the form. Examples of these various ways of reinforcing the walls, of aform are hereinafter described and are shown in the drawings. It will be apparent that destructible form's made according to the present invention are composed entirely of frangible material such as plaster of Paris and paper; and that destruction of the form, after it has served its purpose, may be facilitated by the absorption of moisture by the paper, whether such moisture results from the use of the form in making fuel tanks or cells or other articles, or results from injection of moisture into the form. I The inventionwillbe understood from the following description taken in connection with the accompanying drawings in'which Fig. 1 is a fragmentary view of the inside of the wall of 'a form paper is preferably wiped into liquid plaster of 7 of the form'in fairly'large pieces or sheets; but I' have' found that it'i's often advantageous to tear the paper into pieces havingan area of only a few inches andthen to apply these pieces to In some cases, the paper may be applied to the inner wall having reinforcing paper applied thereto in overlapping pieces; Fig. 2 is a section on the lines 22 of Fig. 1; Fig. 3 is a fragmentary view of the concave inside of a form wall reinforced by corrugated'paper bonded thereto; Fig. 4 is a section on the line 4--4 of Fig'. 3; Fig. 5 is a fragmentaryview of the insideof a rounded form wall reinforced by pressed diinpled paper; Fig. 6 is a-section on the line 6-'-6 of Fig. 5; Fig. 7'is a fragmentary perspective view partly in section,

the inner wall ofthe form in slightly overlapping showing .a. reinforcing fin 'of'paper and plaster bonded together and bonded directly to a form wall; Fig,v 8 is a sectional view showing a reinforcing fin bonded to reinforcing paperwhich is bonded to the inside of a form wall; Fig. 9 shows in elevation how the folded paper used in making a fin may be cut to facilitate application of the rm to the convex surface of a form wall; Fig.

10'shows in elevation 'how the folded paper may be cut to facilitate its application to a concave surface of-a form wall; and Fig. 11 is a plan view showing. how :the folded paper may :be cut to facilitate the making of a bent fin. It will, of course, be understood that folded paper with plaster may be used, in other ways in the form; ing of reinforcing fins, and that those herein described are merely illustrative of that aspect of the invention.

Referring to Figs. 1 and 2, a section of the plaster form wall is shown at l5 as having a smooth outside molded surface l6, and an inside surface I! to which torn pieces of paper l8, I9, 20, 2|, etc., are applied'preferably in overlapping relation. These pieces of paper are wiped into or otherwise smeared with liquid plaster and are In Figs. 1 and 2 the pieces of paper are shown applied in" one layer to the wall of the form; but

it will be understood that two or more layers bonded togetherby plaster maybe employed, as may be necessary to provide proper reinforcing. Another type of'reinforcingis shown in Figs. 3 and 4, in which a fragment of a wall of a form is shown at 24', with'its smooth outer molded surface represented at 25. To the inner surface ofthe plaster wall 24, a piece. of corrugated paper 26 is bonded by being firstsmeared on one side with wet plaster and then pressed against the wet plaster of the wall 24. .In this case, as in the construction shown in Figs. 1 and 2, the corrugated papenmay be torn or cut into comparatively small pieces and applied in overlap-v ping relation, in order to eliminate air pockets between the paper- 26 and the plaster wall .24.

Figs. 5. and 6 represent a construction similar to that represented in Figs. 3 and4, except that pressed dimpled paper 28 is applied to the inside surface of; a rounded form wall 2%, the outside smooth molded surface of which is indicated at 30.. As described in connection with Eigs. 1 and 2, thedimpled paper 28, of course may be applied in overlapping pieces. perlends itself particularly well to the reinforce ing of rounded formwalls.

Such pressed pa-.

and-plaster fi which is bonded to the first mentloned paper.

Destructible forms may be of a great variety of shapes, and it may be desirable to apply reinforcing fins to convex surfaces, to concave surfaces, and in a bent as well as a straight line. As has been hereinbefore mentioned, it is convenient to fold the paper used in the fins in advance of its use; and when such paper is to be used in making curved or bent fins it should be cut in one or more of the ways illustrated in Figs. 9, l0 and 11. Fig. 9 shows in elevation how the adjacent folds of a fin paper may be out at down to the wings to facilitate the use of the paper in the making of a fin applied to a convex form wall 46. Fig. 10 shows in elevation how the adjacent folds of the fin paper may be cut to form notches 48, to facilitate use of the paper in the making of a fin applied to a concave form wall 49. Fig. 11 shows in elevation how the wings 38 and 39 of a fin paper may be cut at 5.0 and notched at St to facilitatev the making of a bent fin. It will be obvious that .by cutting the'fin paper in the manner shown inFigs. 9, l9 and 11 the making of curved and bent composite fins of 'papereand-plaster is facilitated. After such fins have been applied to the inside of a form wall, and the plaster has set, the fins provide a very rigid reinforcee ment of the form wall. Therefore, the use of such fins makes possible the making of comparatively thin form walls which are strong and Fig. 7 shows a section of form wall 34 reinforced bya fin bonded to said wall. As will be clear from Fig. Z, this reinforcingfin comprises a piece of paper which has been wiped into or otherwise; smeared with wet plaster on one side, folded into. the shape shown, and then applied to. the innersurface of; the plasterform wall 34 when the latter is in a wet condition, thereby producing bonding of the composite papereandplaster fin to, the form wall. Asv will be apparent, the. paper is so 'folded'that its cross-section re.- sembles the. letter T- (inverted'as. shown in Fig. 7) with adjacent folds 36v and 31' and wings 3.8 and 3,9. Creasi'ng of: the paper will generally be found to. be desirable-before it is smeared with plaster; and enough plaster. should be smeared on to. produce. a. thin layer between the adjacent folds. 3.6 and; .31 of the paper, and to. provide for bonding of the wings and 39 to. the plaster of the. form wall 3.4.

Fig. 8.shows. a structure which issimilar to Fig.

7-, except that the inner surface of the form wall 4.0; is reinforced with pieces of paper- 4.1 (in the manner. described in connection with Figs. 1 and 2). before the. reinforcing fin is/ applied. Thus, with the construction shown. in Fig. 8, the-form Wall 411 is reinforced both] bythe paper M. bonded to. its inner surfaceand by the composite paper? rigid, even though such walls may be of consider able length and'width. Thus the making of a satisfactory, light form is facilitated; and the materials used to make the form are readily destructible after it has served its purpose.

What is claimed is:

1. Ina destruotible hollow form which in outside shape and size conforms to the space within a hollow article which is tobe made on said form, a wall composed of molded frangible plaster material reinforced and strengthened plaster with paper bonded to the inside of the molded'frangible material of the wall.

-2. In a destructible hollow formwhich in outside shape and size conforms to the space within a hollow article which is to be made on said form, a wall composed of molded frangible material reinforced with pieces of paper arranged in overlapping relation and bonded together and to thev inside of the molded frangible material of the wall.

3. Ina destructible hollow form which in outside shape and size conforms to the space within a hollow article which is to'be made on said form. a wall composed of molded frangible material reinforced with a plurality of layers of pieces of paper arranged in overlapping relation and bonded together and to the inside of the molded frangible. material of the wall.

4. In a destructible hollow form which in outside shape and size conforms to the space within a hollow article which is to be made on said form, a wall composed of molded frangible material reinforced with pressed paper having sur-. faces other than plane surfaces bonded to the inside of the molded frangible material of the wall.

5. In a destructible hollow form which in out? side. shape and size conforms to the space within.

a, hollow article which is. to be madev on said form, a wall composed of molded frangible ma-.

terial. reinforced by a fin composed of paper and frangible material bonded together and bonded to the inside of the molded frangible material of the wall.

6. In a destructible'hollow form which in outside shape and size conforms to the space within a hollow article which is to be made on said form,

I f a wall composed of molded frangible material reinforced by a fin composed of folded paper enclosing frangible materialbonded to the paper and to the inside of the molded frangible ma: terial of the Wall.

7. In a destructible hollow form which in outside shape and size conforms to the space within a hollow article which is to be made on said form, a wall composed of molded frangible to the folded paper and to the first mentioned 9. In a destructible hollow form which in outside shape and size conforms tothe space within a hollow article which is to be made on said form, a wall reinforced by a fin composed of paper folded so that its transverse cross-section resembles the letter T and also composed of frangible material enclosed within the paper and bonded thereto and to the inside of the wall.

10. In a destructib-le hollow form which in outside shape and size conforms to the space within a hollow article which is to be made on said form, a wall reinforced by a fin composed of as to conform generally to the curved wall of the i form, said fin being also composed of frangible paper folded so that it has adjacent folds and wings, said fin being also composed of frangible material enclosed within the adjacent folds of the paper and bonded thereto andto the wings of the paper and to the inside of the wall.

11. In a destructible hollow form which in outside shape and size conforms to the space within a hollow articlewhich is to be made on said form, a lcurved wall reinforced by a curved fin composed of paper folded so that it has adjacent v folds and wings, the adjacent folds of said paper being cut and the folded paper being bent so material enclosed within the adjacent folds of the paper and bonded thereto and to the wings of the paper and to the inside of the wall.

Y 12. In a destructible hollow form which in outside shape and size conforms to the space'within a hollow article which is to be made on said form,

a wall reinforced by a bent fin composed of paper folded so that it has adjacent [folds and wings, the wings of the folded paper being cut and the adjacent folds of said paper being bent at the point of cutting, said fin being .also composed of frangible material enclosed within the adjaoent folds of the paper and bonded thereto and to the wings of the zfoldedpaper and to th inside of the wall.

LILLIAN L. GRENEKER.

CERTIFICATE OF CORRECTION. a Patent No. 2,569,892. February 2o 19h LILLIAN L GRENEKER.

It is hereby certified that error appears in theprintedspeoification =of the above numbered patent requiring correction as follows: Page 2, sec- 0nd column, line l5; claim 1, strike out "plaster" and insert the same before "material" in line b5, same claim; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. t

Signed and sealed this 12th day of June, A. D. 9 -l-5- Leslie Frazer (Seal) R Acting Commissioner of Patents. 

